Who could have done such immense evil? I have asked this question as many times as I have seen the pictures on television. Every viewing fills me with unspeakable sadness. Are people calling themselves Muslims capable of such atrocities? Are they reading the same Koran? Are they the followers of the same Prophet Muhammad?

As a Muslim writer, I am expected to know the answer. People ask me to explain the mind and motivation of terrorists and seek Islamic explanation for the actions of the hijackers. My neighbour wants to know what kind of Muslim does such horrendous things. They believe I can provide a rationale for how people become suicide bombers, mass murderers and justify their evil.

I tell them what the Koran says: 'Even if you stretch out your hand against me to kill me, I shall not stretch out my hand against you to kill you. I fear Allah, the Lord of the World.' I paraphrase the teachings of the Prophet Muhammad: the murder of one innocent person is akin to the murder of the whole of humanity. I tell them that the Prophet forbade the killing of civilians, women and children, the old and infirm, the wanton destruction of property, burning of crops and slaughter of animals, even in a full-scale war.

They ask me about martyrdom. 'Aren't the suicidal hijackers buying a ticket straight to heaven?' Islamic theology, I tell them, is not a business transaction. No one, but no one, knows where they'll end up. Only God knows. Even the Prophet wept with fear that he may not be forgiven. The Islamic doctrine of martyrdom was crystallised in the action of Imam Hussain, the grandson of Prophet Muhammad on the battlefield of Kerbala in October 680AD. He stood with his 70-odd followers against an army of 4,000 well-equipped soldiers, to uphold justice against injustice in the full knowledge that it would cost him his life. His sacrifice was the inevitable consequence of holding firm to what is morally right, not a sought-after, self-chosen, wilful self-sacrifice of one acting beyond any moral or ethical restraint. Suicide hijackers disdain the preciousness of each and everyone of God's creation, themselves and their victims; they cheapen the name of martyr.

To sacrifice one's property, security and comfort and, if there is no other way, one's life, for the cause of what is right and just is martyrdom for all faiths. But faith also teaches the limits of human understanding, that we will all be judged and the meaning of our actions made clear by the Most Compassionate, the All Knowing. Martyrdom, like life, is the gift and judgment of God, not of men. Only within the bounds of belief, within attachment to the duties of faith, can anyone hope to walk the path to paradise.

Neither is the paradise of Islam some kind of brothel that provides the services of '70 virgins' to its denizens - the nonsense the press attributes to these murderous paradise-seekers. Far from being an abode of pleasure, the paradise of the Koran is a place of sublime innocence. The 'virgins', or 'houris', derive their name from the eyes of gazelles. They personify beauty and innocence; these eyes have never cast their gaze on sin. In the gardens of paradise, the houris utter only one word: 'Peace, peace.'

Creating the Kingdom of God on earth, as it is in heaven, is the basic message of Islam. This is the true meaning of jihad. Now there's a word. The very mention of the term sends shivers down 'civilised' spines and leads many, glibly, towards 'holy war'. Surely, these paradise-seeking martyrs have declared jihad on America? Acts of terror are not jihad. They violate the explicit word of God, Prophet Muhammad and the reasoned consensus of all believers. The greatest jihad is the war on injustice in one's own soul, the injustice that can conceive of terror tactics and lose all restraints and respect for the sanctity of a human life. Jihad is the reasoned struggle of each individual to work within the bounds of moral action, to extend the protection of justice equitably to every human being, irrespective of colour, creed or place of origin. Jihad is the obligation to make peace a lived reality for all human beings.

All this, the belief of the vast majority of Muslims, is the antithesis of the credo of the suicide bombers. We try to live a good life in hope of paradise. We seek to do justice that paradise may be granted to us. We walk humbly before God, not claiming divine assurances as our own prerogative. In case you are wondering, I am paraphrasing a Biblical verse, from the Book of Micah (6:8) in the Old Testament, a common framework for Jews, Christians and Muslims alike.

Islam cannot explain the actions of the suicide hijackers, just as Christianity cannot explain the gas chambers, Catholicism the bombing at Omagh. They are acts beyond belief, religious belief, by people who long ago abandoned the path of Islam.

The faith I hold, the faith of Muslims, the justice we seek is an obligation to promote and make real in each life freedom from tyranny, neglect, need, dearth and suffering. The justice we yearn for is the life blood of a humane society with dignity and freedom for all. It cannot be found by blasting innocents apart in an inferno of twisted metal and concrete. When the innocent are murdered, we all go into the dark with them. When the innocent suffer, their suffering is ours.

 Ziauddin Sardar is a leading Muslim writer. His Introducing Muhammad is published by Icon Books, £8.99